A genetic variant of CXCR4 predicts pegylated interferon-alpha treatment response in HBeAg-positive chronic hepatitis B patients

Chemokine receptor 4 (CXCR4) plays a vital role in immunoregulation during hepatitis B virus (HBV) infection. This study aimed to screen single-nucleotide polymorphisms (SNPs) of CXCR4 for predicting pegylated interferon-alpha (PegIFN alpha) therapy response in chronic hepatitis B (CHB) patients. This retrospective cohort study enrolled a total of 945 CHB patients in two cohorts (Cohort 1, n = 238; Cohort 2, n = 707), and all the patients were hepatitis B e antigen (HBeAg)-positive and treated with PegIFN alpha for 48 weeks and followed up for 24 weeks. Twenty-two tag SNPs were selected in CXCR4 and its flanking region. A polygenic score (PGS) was utilized to evaluate the cumulative effect of multiple SNPs. The relationships between CXCR4 SNPs and PGS and PegIFN alpha treatment response were explored in the two cohorts. Among the 22 candidate SNPs of CXCR4, rs28367495 (T > C) was significantly linked to PegIFN alpha treatment response in both cohorts. In patients with more number of rs28367495 C allele, a higher rate of combined response (CR, defined as HBeAg seroconversion and HBV DNA level < 3.3 log(10) IU/mL; P = 1.51 x 10(-4)), a lower mean hepatitis B surface antigen (HBsAg) level (P = 4.76 x 10(-4)), and a higher mean HBsAg decline (P = 3.88 x 10(-4)) at Week 72 were achieved. Moreover, a PGS integrating CXCR4_rs28367495 and five previously reported SNPs was strongly correlated with CR (P = 1.26 x 10(-13)), HBsAg level (P = 4.90 x 10(-4)), and HBsAg decline (P = 0.005) in all the patients of the two cohorts. CXCR4_rs28367495 is a promising indicator for predicting the responsiveness to PegIFN alpha treatment for HBeAg-positive CHB patients. The new PGS may further improve the prediction performance.